Electrolytic processing unit device, and method for electrolytic processing, washing, and drying

ABSTRACT

An electrolytic processing unit device includes an electrolytic processor for performing electrolytic processing on a wafer, a washer for washing the processed wafer, and a drier for drying the wafer. The electrolytic processor, the washer, and the drier are placed in one processing chamber to form one module. In this manner, the electrolytic processing procedure, the washing procedure, and the drying procedure for wafers can be continuously carried out in one place.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an electrolytic processing unit device,and a method for electrolytic processing, washing, and drying. Moreparticularly, the present invention relates to an electrolyticprocessing unit device that is used for performing electrolyticprocessing, washing, and drying for wafers, and a method for theelectrolytic processing, washing, and drying.

2. Description of the Related Art

In a conventional CuCMP electrolytic polishing, for example, the seriesof procedures for electrolytic processing, washing, and drying for eachwafer is carried out in modules that are independent of one another.Therefore, each wafer needs to be transported through the correspondingmodule in each of the procedures for electrolytic processing, washing,and drying. Accordingly, the number of wafer transporting proceduresbetween the modules is large.

Particularly, in the electrolytic processing for each wafer, the wafertransportation system becomes more complicated, as the wafer is normallyturned over so as to process both sides of the wafer.

If some trouble is caused in one of the modules while a wafer is beingtransported sequentially to the respective modules of the respectiveprocedures for performing electrolytic polishing on the wafer, thetrouble leads to a large problem. For example, if trouble is caused inthe module of the washing procedure during a processing operation, andthe operator does not notice the trouble and cannot cope with thetrouble immediately, the wafer transportation system is stopped in themodule of the washing procedure, and this delay affects the modules ofthe other procedures. As the transportation systems of the other modulesare also stopped, all the wafers being transported along the processline are stopped. The stopped wafers are left in contact with the outerair and the process liquids over a long period of time, and problemssuch as oxidation degradation and corrosion are caused.

To avoid the above problems, there has been a method suggested foractivating the program for production control so as to immediately stopthe transportation of wafers in the modules of all the procedures andkeep the wafers away from the process line when trouble is caused duringthe electrolytic processing procedure (see Japanese Patent ApplicationNo. 2002-178236, for example).

However, creation of the above program is very complicated according toa method such as the above described method by which the transportationof wafers in the modules is immediately stopped and the wafers are keptaway from the process line when trouble is caused. In a conventional CMPdevice, mechanical processing is performed mostly on wafers, and aplaten for rotating the wafer polishing pad is required. However, anelectrolytic processing device does not require the platen.

If there is trouble in the last drying procedure in a case where anoperation is performed in modules for procedures of processing, washing,and drying in a device, many wafers are stopped within the device unlessthe trouble is eliminated. Particularly, if wafers are stopped and leftin the processing procedure and the washing procedure, the surfaces ofthe wafers might be oxidized, or the surfaces might be etched by thewashing solution. As a result, the quality of the wafers might bedegraded. In such a case, if even very small trouble caused in theinitial stage is left unnoticed and wafers are stopped in the device,all the wafers in the device might be wasted, which is a seriousproblem.

In view of these facts, since trouble in one of the modules forprocedures greatly affects the other wafers when a large number ofwafers are processed at once, close attention needs to be paid tooperations of the device. Therefore, unmanned operations have beenimpossible in practice.

In a Cu low-k process, the atmosphere in the wafer electrolyticprocessor needs to be made different from the air, so as to preventoxidation of the surface of the wafer especially during the electrolyticprocessing. Further, in the drying procedure after the washing, theatmosphere in the electrolytic processor also needs to be made differentfrom the air, so as to reduce watermarks.

If the atmosphere control is performed in many modules, the atmospherecontroller becomes very large in size. Also, if the atmosphere controlis performed every time a wafer is brought in or out in each procedure,a very long period of time is required. If the atmosphere control needsto be performed only once for the series of procedures for processing,washing, and drying, a very efficient operation can be realized.

Where two or more modules are prepared for two or more procedures,devices for transporting each wafer between the modules are necessary.Those transporting devices are very costly. Moreover, at the time ofmaintenance, all the procedures for wafers are interrupted, and theoperation rate of the device becomes lower.

Further, in a conventional electrolytic processing operation, it hasbeen difficult to perform Cu electrolytic processing and Ta electrolyticprocessing on each wafer in the same position.

Even in electrolytic processing, a mechanism for energization isprovided in a chemical mechanical polishing device to performelectrolytic processing. As the pad for chemical mechanical polishing, aregular polishing pad is used. However, when Ta polishing is performedafter Cu polishing, the Cu polishing waste adversely affects the Tapolishing. For example, the Ta polishing rate might change, or the Cupolishing waste might adhere to the Ta surface. Also, in a case wherethe electrolytic solution for Cu polishing is different from theelectrolytic solution for Ta polishing, the two electrolytic solutionsmight be mixed with each other on the polishing pad. Therefore, in acase where electrolytic polishing is performed with a polishing pad, itis difficult to perform both Cu polishing and Ta polishing in onemodule.

Likewise, in a case where the polishing procedure and the polishingprocedure are carried out in one module, electrolytic solutions andabrasive grains existing on the polishing pad cause the washingenvironment to deteriorate.

As disclosed in U.S. Pat. No. 7,084,064 and Japanese Patent ApplicationLaid-open No. 2006-135045, it has been almost physically impossible tocombine an electrolytic processing device and a washing device into oneby conventional techniques. This is because an electrolytic processingdevice has a platen, and processes the entire surface of each wafer atonce. Normally, a wafer is held by a wafer head provided above thewafer, and a platen is placed under the wafer. In this case, polishingis performed, with the wafer being held to face downward.

The wafer may be also washed while facing downward, but a washingsolution cannot be applied to the surface of the wafer in this situationin reality.

In an electrolytic processing device disclosed in Japanese PatentApplication Laid-open No. 2002-93761, the electrode portion is processedabove a wafer while being swept. However, since each wafer is processedwhile being immersed in an electrolytic solution, it is difficult toincorporate the washing procedure and the drying procedure into theelectrolytic processing procedure.

To combine an electrolytic processing device, a washing device, and adrying device, the same technique should be utilized for clamping wafersin those devices. Also, to transport wafers to wafer chucks, atransportation mechanism that does not physically interfere with theelectrolytic processing unit, the washing unit, and the likes needs tobe prepared.

However, it has been impossible to realize all of those functions, andcombine all the modules into one module structure. Also, it has beenphysically difficult to combine the modules for supplying electrolyticsolutions, controlling electrolytic processing, and washing wafers, intoone.

Also, if a polishing slurry or the like remains in the unit forelectrolytic processing, the polishing slurry dries and adheres to thewall faces of external units. The dry polishing slurry turns into powerdust that lies scattered about in the module. As a result, it isdifficult to keep a clean environment for the washing device.

In view of these facts, an electrolytic processing device and washingand drying devices for washing and drying each wafer to a normal statebefore each wafer is sent back to the semiconductor factory cannot beplaced in one module by conventional techniques. If those devices areforced into one module, a clean environment cannot be kept.

Also, if trouble is caused in one of the procedures of electrolyticprocessing, washing, and drying for wafers in a case where thoseprocedures are combined into one module, the transportation of wafersbeing transported in other modules is not stopped. If the other wafersare stopped, the surface of each wafer is reformed. In this case, smalltrouble results in significant trouble that ruins all the wafers.

SUMMARY OF THE INVENTION

The object of the present invention is to solve the above problems. Morespecifically, according to the present invention, the procedures beingcarried out sequentially in a device are not interrupted, and theoperation rate does not rapidly drop. Instead, each module performs anoperation independently of other modules. If there is some troublecaused in one module, the other modules keep operating. In this manner,the entire operation rate does not rapidly drop, and a stable operationrate is kept. Also, wafer transporting devices for connecting modulesfor the respective procedures are not required, and an increase indevice size due to the transporting devices can be prevented.

Also, according to the present invention, the atmosphere in theelectrolytic processing procedure does not adversely affect theatmosphere in the later washing procedure, or particles are notscattered about. The adverse influence of the atmosphere in theelectrolytic processing procedure is the problem normally expected froma combination of the electrolytic processing procedure and the washingand drying procedures by a conventional technique. The present inventionalso eliminates the adverse influence of the contamination caused by theCu material that is dissolved by an electrolytic solution and adheresback to the surface. By doing so, the electrolytic solution having beenused for electrolytic processing cannot be brought into the nextelectrolytic processing procedure and the next washing procedure.

In a case where each wafer is transported to more than one module formore than one procedure, all the wafers being transported in the deviceare temporarily stopped every time a maintenance operation is performed,and the operation rate of the device becomes lower. The presentinvention is to solve those technical problems.

The present invention has been made to solve the above problems, andaccording to a first aspect of the present invention, there is providedan electrolytic processing unit device including: an electrolyticprocessor that performs electrolytic processing on a wafer; a washerthat washes the processed wafer; and a drier that dries the processed orwashed wafer, the electrolytic processor, the washer, and the drierbeing placed in a processing chamber to form one module that performsthe electrolytic processing, washing, and drying for the wafer.

In this structure, the electrolytic processing unit device has theelectrolytic processor, the washer, and the drier placed in oneprocessing chamber to form one module. Accordingly, the waferelectrolytic processing, washing, and drying can be continuouslyperformed in one place. Also, even if some trouble is caused in onemodule, the trouble does not affect other modules at all, and it is notnecessary to stop the wafer processing procedures in other modules.

According to a second aspect of the present invention, there is providedthe electrolytic processing unit device according to the first aspect,wherein the electrolytic processor, the washer, and the drier arealigned on a circular arc or a straight line.

In this structure, the electrolytic processor, the washer, and the drierof the electrolytic processing unit device are arranged along a circulararc or a straight line. Accordingly, when a wafer is transported to theelectrolytic processor, the washer, and the drier, only one robot thatcan move along the circular arc or the straight line is required for thewafer transportation.

According to a third aspect of the present invention, there is providedthe electrolytic processing unit device according to the first or secondaspect, wherein the electrolytic processor, the washer, and the drierform one module, and are connected to each other by one transportationsystem.

In this structure, the electrolytic processor, the washer, and the drierof one module are connected by one transportation system. Accordingly,only one device is required for transporting wafers to the electrolyticprocessor, the washer, and the drier. Thus, each wafer can betransported to the electrolytic processor, the washer, and the drier ina sequential manner.

According to a fourth aspect of the present invention, there is providedthe electrolytic processing unit device according to any of the first tothird aspects, wherein the electrolytic processor, the washer, and thedrier that carry out the above series of procedures are controlled,operated, and subjected to maintenance independently of one another.

In this structure, the electrolytic processor, the washer, and the driercan be operated, controlled, and subjected to maintenance independentlyof one another. Accordingly, when one of the electrolytic processor, thewasher, and the drier is operated, controlled, and subjected tomaintenance, the other procedures do not need to be stopped.

According to a fifth aspect of the present invention, there is providedthe electrolytic processing unit device according to the first or secondaspect, wherein a beveling unit for beveling an outer peripheral portionof the wafer after the electrolytic processing is provided in thevicinity of the electrolytic processor.

In this structure, when the conductive film on the surface of the waferis removed from the center toward the outer peripheral portion of awafer, a ring-like portion of the conductive film remains at the outerperipheral portion of the wafer. However, the ring-like conductive filmis beveled by etching or mechanical processing performed by a bevelingunit provided in the vicinity of the electrolytic processor.Accordingly, each wafer subjected to electrolytic processing is notmoved away from the electrolytic processor, and is then subjected tobeveling.

According to a sixth aspect of the present invention, there is providedthe electrolytic processing unit device according to any of the first,third and fourth aspects, wherein the module includes: an access areathrough which wafers are brought in and out; an electrolytic processinghead for electrolytic processing that is provided in a different areafrom the access area, and a holding arm that holds the electrolyticprocessing head; and a washing arm that supports a wafer washing unit isprovided in the opposite position from the holding arm.

In this structure, a washing arm supporting a wafer washing unit isprovided in the opposite position from the holding arm that holds theelectrolytic processing head. Accordingly, washing of each wafer isperformed at a spot separated from the spot for electrolytic processing.

According to a seventh aspect of the present invention, there isprovided the electrolytic processing unit device according to the sixthaspect, wherein the wafer washing unit in the module includes a washingbrush, a ultrasonic water supplier, and a nitrogen blower.

In this structure, the wafer washing unit includes a washing brush, aultrasonic water supplier, and a nitrogen blower. Accordingly, theelectrolytic solution remaining on the surface of the wafer is removedby washing with the brush and ultrasonic washing, and the spacesurrounding the wafer cannot become an oxygen atmosphere at the time ofwashing.

According to an eight aspect of the present invention, there is providedan electrolytic processing unit device including: an electrolyticprocessor that performs electrolytic processing on a wafer; a washerthat washes the processed wafer; and a drier that dries the processed orwashed wafer, the electrolytic processor, the washer, and the drierbeing placed in a processing chamber to form one module that performsthe electrolytic processing, washing, and drying for the wafer, anelectrode portion for the electrolytic processing being made of aninorganic material.

This structure has the same effects as the first aspect of theinvention, and the electrode portion for electrolytic processing is madeof an inorganic material. Unlike a case with an electrode portion madeof an organic material, the old electrolytic solution used for electrodeprocessing can be easily rinsed off from the electrode portion, and theold electrolytic solution cannot remain at the electrode portion.

According to a ninth aspect of the present invention, there is provideda method for electrolytic processing, washing, and drying in a structurehaving a wafer chuck mechanism, including the steps of: performingelectrolytic processing by applying a voltage between an electrodehaving edges clamped around a wafer and an electrolytic processing headthat scans the surface of the wafer, after securing the wafer; polishinga conductive film at an edge portion in the same position, if necessary,while a bottom face of the wafer is being sucked and fixed after an edgeclamp is removed; scanning the surface of the wafer with a washing armin the same position, a washing unit being attached to the washing arm;washing the processed wafer; and drying the processed or washed wafer inthe same position.

By this method, the series of procedures of electrolytic processing,edge processing, washing, and drying for wafers can be carried out inthe same place. Accordingly, wafers do not need to be moved for eachprocedure.

According to a tenth aspect of the present invention, there is providedthe method according to the ninth aspect, wherein the surface of thewafer and an electrode portion are rinsed with pure water, after theelectrolytic processing procedure and the washing procedure.

By this method, the surface of each wafer and the electrode portion arerinsed with pure water after electrolytic processing and washing.Accordingly, the electrolytic solution and chemical solution (washingsolution) remaining on the surface of the wafer can be removed after theelectrolytic processing and washing of the wafer.

According to the first aspect of the invention, electrolytic processing,washing, and drying for each wafer can be performed in one place. Withthis arrangement, a large space is not required, and each wafer does notneed to be transported through more than one module as in the prior art.Accordingly, the mechanism such as a wafer transporting device can beomitted. Also, even if some trouble is caused in one module, the wafersbeing transported through the process line do not need to be stopped byinterrupting the operation of the transportation systems of othermodules. Thus, oxidation degradation and corrosion due to theinterruption are not caused in wafers, and it is unnecessary to create acomplicated program.

According to the second aspect of the invention, each wafer can betransported to the electrolytic processor, the washer, and the drier byone robot. With this structure, the same effects as those of the firstaspect of the invention can be achieved, and the wafer transportingmechanism can be made simpler than a conventional one. Also, theelectrolytic processor, the washer, and the drier can be arranged alonga circuit arc or a straight line, in accordance with the situation andobjective. Thus, a higher degree of freedom is allowed in thearrangement of the electrolytic processor, the washer, and the drier.

According to the third aspect of the invention, only one device isrequired for transporting wafers to the electrolytic processor, thewasher, and the drier. With this structure, the same effects as those ofthe first or second aspect of the invention can be achieved, and thecosts for the wafer transportation can be reduced. Also, the operationrate of the wafer transportation system can be made higher.

According to the fourth aspect of the invention, even when one of theelectrolytic processor, the washer, and the drier is being operated,controlled, or subjected to maintenance, the operations and the likes inother procedures are not interrupted and can be continued. With thisstructure, the same effects as those of any of the first to thirdaspects of the invention can be achieved, and the operating rates of theelectrolytic processor, the washer, and the drier can be made higherthan in conventional cases.

According to the fifth aspect of the invention, the conductive filmremaining at the outer peripheral portion of each wafer afterelectrolytic processing can be subjected to beveling performed by thebeveling unit provided in the vicinity of the electrolytic processor.With this structure, the beveling can be performed immediately after theelectrolytic processing. Thus, the same effects as those of the first orsecond aspect of the invention can be achieved, and higher efficiencycan be expected in the beveling process.

According to the sixth aspect of the invention, the washing of eachwafer can be performed at a spot separated from the spot forelectrolytic processing. With this structure, the same effects as thoseof any one of the first, third, and fourth aspects of the invention canbe achieved, and the electrolytic solution used for electrolyticprocessing cannot be brought into the washer.

According to the seventh aspect of the invention, the electrolyticsolution remaining on each wafer can be removed by washing with thebrush and ultrasonic washing, and the space surrounding each wafercannot become an oxygen atmosphere during the washing. With thisstructure, the same effects as those of the sixth aspect of theinvention can be achieved, and the effectiveness of washing each wafercan be increased. Thus, adverse influence of an oxygen atmosphere oneach wafer can be eliminated in advance.

According to the eighth aspect of the invention, the same effects asthose of the first aspect of the invention can be achieved. Morespecifically, the mechanism for wafer transportation can be omitted, andoxidation degradation and corrosion of wafers can be prevented. Also, itbecomes unnecessary to create a complicated program. In addition tothose effects, the old electrolytic solution used for electrodeprocessing does not remain at the electrode portion. Accordingly, whenelectrode processing is performed with a new electrolytic solution, theold electrolytic solution does not react with the new electrolyticsolution, and does not adversely affect the electrolytic processing.

The tenth aspect of the present invention provides the method forelectrolytic processing, washing, and drying according to the ninthaspect, characterized in that the surface of each wafer and theelectrode portion are rinsed with pure water after the electrolyticprocessing procedure and the washing procedure.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view showing an exemplary structure of an electrolyticprocessing unit device in accordance with an embodiment of the presentinvention;

FIG. 2 is a cross-sectional view showing the electrolytic processor ofthe electrolytic processing unit device of FIG. 1;

FIG. 3 is a schematic perspective view illustrating a state formed byprocessing of the electrolytic processing unit device of the embodiment;

FIG. 4 is a flowchart showing an example of processing procedures to becarried out by the electrolytic processing unit device of thisembodiment;

FIG. 5 is a plan view showing an example arrangement of an electrolyticprocessing unit device of the present invention;

FIG. 6 is a plan view showing another example arrangement of anelectrolytic processing unit device of the present invention; and

FIG. 7 is a plan view showing yet another example arrangement of anelectrolytic processing unit device of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

To combine the wafer electrolytic processing procedure, the washingprocedure, and the drying procedure into one module, to prevent eachwafer from stopping in other modules even if some trouble is caused inone of the procedures, and to make a complicated program unnecessary,the present invention provides an electrolytic processing unit devicethat includes an electrolytic processor for performing electrolyticprocessing on a wafer, a washer for washing the processed wafer, and adrier for drying the processed or washed wafer, and performs theelectrolytic processing, the washing, and the drying of the wafer in onemodule that is realized by placing the electrolytic processor, thewasher, and the drier in one processing chamber.

Embodiment

The following is a description of a suitable embodiment of the presentinvention, with reference to FIGS. 1 through 7. This embodiment isapplied to an electrolytic processing unit device that performselectrolytic processing, washing, and drying of a wafer formed withconductive films. FIG. 1 is a plan view showing an exemplary structureof the electrolytic processing unit device in accordance with thisembodiment. FIG. 2 is a cross-sectional view showing the electrolyticprocessor of the electrolytic processing unit device of FIG. 1. FIG. 3is a schematic perspective view illustrating a state formed byprocessing of the electrolytic processing unit device. FIG. 4 is aflowchart showing an example of processing procedures to be carried outby the electrolytic processing unit device. FIGS. 5 through 7 are planviews each showing an example of arrangement of an electrolyticprocessing unit device of the present invention.

As shown in FIG. 1, the electrolytic processing unit device 1 includesan electrolytic processor 2 that performs electrolytic processing on awafer W, a washer 3 that washes the processed wafer W, and a drier 4that dries the processed or washed wafer W. The electrolytic processor2, the washer 3, and the drier 4 are placed in a processing chamber (acleaning room) 5, and the wafer W is transported to the processingchamber 5 by a transfer robot 6. With this arrangement, the series ofprocedures of electrolytic processing, washing, and drying of the waferW can be carried out in the processing chamber 5. The modules forprocessing procedures that have been three or more in number by aconventional technique are integrated into one.

In this electrolytic processing unit device 1, electrolytic processing,washing, and drying of the wafer W are carried out in predeterminedorder by the electrolytic processor 2, the washer 3, and the drier 4.

In the electrolytic processor 2, a carbon electrode is attached to thetop end of the arm. This carbon electrode may have a brush-like form ora felt-like form. Alternatively, the carbon electrode may be in a thin,tile-like form. If the carbon electrode is brought into direct contactwith the wafer, the wafer is damaged. Therefore, the carbon electrode isprocessed in a semi-contact state via a thin electrolyte film. Here,electrolytic dissolution processing is mainly performed. Instead of acarbon electrode, a wire rod made of a metal material may be used.

In any case, the electrode should not be made of a material containingan electrolytic solution, like a polymeric polishing pad. A polishingpad used in chemical mechanical polishing is made of foamedpolyurethane, which contains a polishing agent. When a polishingmaterial is processed with an electrolytic solution, the oldelectrolytic solution contained in the polishing pad might exude andreact with the new electrolytic solution.

Therefore, it is necessary to use an inorganic material that does notcontain a used electrolytic solution and is not an organic material.With an inorganic material, even if an electrolytic solution containingabrasive grains is used for example, the electrode portion is rinsed inadvance. In this manner, the electrolytic solution can be easily rinsedoff, and, as a washing atmosphere, does not adversely affect the nextwashing process.

After the electrolytic processing, pure water is supplied to the surfaceof the wafer W from a pure water nozzle (not shown) directed to thesurface of the wafer W, and the entire surface of the wafer W isthoroughly rinsed. Through this rinsing process, the electrolyticsolution remaining on the surface of the wafer W is replaced with purewater. Also, a shower nozzle for supplying pure water to be used forwashing is provided within a cup (not shown) surrounding the wafer W.This shower nozzle is designed to thoroughly rinse off the electrolyticsolution scattering from the wafer W inside the cup.

The electrode used for the electrolytic processing and provided at thetop end of the arm is removed from the position for processing the waferW. A pot filled with pure water is prepared in a stand-by position at adistance from the wafer processing position. The electrode material isimmersed in the pure water in the pot, so that the electrolytic solutionremaining on the electrode is washed off. Pure water is constantlysupplied into the pot, so that the pot is always in an overflowingstate. Even if the electrode material is a carbon brush or the like, theelectrolytic solution remaining between the bristles of the brush due toa capillary absorption phenomenon is thoroughly rinsed off by ultrasonicwaves.

In the above described structure, the mechanism for rinsing the surfaceof the wafer W and the electrode material is provided so as not to leavethe electrolytic solution in the later washing procedure after theelectrolytic processing. With this structure, the electrolyticprocessing state is not continued into the next washing procedure, andwashing can be performed in a clean environment.

The electrolytic processor 2 performs primary processing and secondaryprocessing so as to remove a conductive film from the surface of thewafer W. Also, a beveling unit 7 is provided in the electrolyticprocessor 2, and the beveling unit 7 performs beveling on the edgeportions remaining on the outer peripheral portion of the wafer W afterthe removal. Further, an application mechanism (not shown) for applyingan antioxidant solution to the wafer W after the secondary processing iscompleted is provided in the electrolytic processor 2.

FIGS. 2 and 3 show a specific example of the electrolytic processor 2.Reference numeral 8 indicates a wafer holding table that has the wafer Wplaced and fixed thereon, and can be rotatively driven. A fixing unit 9for placing and fixing the wafer W is provided at the upper face portionof the wafer holding table 8. In the example shown in the drawings, avacuum chuck unit is provided.

Further, a processing head 10 is provided above the wafer holding table8. As shown in FIG. 3, a processing electrode 11 is provided at the topend of the processing head 10, so as to face the upper face of the waferW, with a very small space being left between the processing electrode11 and the upper face of the wafer W. The processing head 10 is attachedto a movable member 12 such as an arm or a slider provided in thevicinity of a side of the wafer holding table 8. In the example shown inthe drawings, the processing head 10 is attached to the top end of thedouble-arm movable member 12, and the base portion of the movable member12 is linked to the upper portion of a vertical axis 13 having anadjustable height. The base portion of the movable member 12 isconnected to the upper portion of the vertical axis in a horizontallyrotatable fashion. Accordingly, the processing head 10 is horizontallyrotated from the center of the wafer W toward the outer peripheralportion, so that the processing electrode 11 moves outward in the radialdirection of the wafer W.

At the outer peripheral portion of the wafer W, there are six detachablewafer chucks 21 through 26 that rotate integrally with the wafer holdingtable 8. These wafer chucks 21 through 26 are arranged at regularintervals in the outer circumferential direction of the wafer W. Also,the wafer chucks 21 through 26 can move back and forth, and areadjustable up and down with respect to the outer peripheral portion ofthe wafer W on the wafer holding table 8. Further, supply electrodes Athrough F for supplying power to the wafer W are provided inside therespective wafer chucks 21 through 26. Each of the supply electrodes Athrough F is sealed and protected, so as to prevent liquid and the likesfrom entering the supply electrodes A through F. A tester (not shown)for measuring the mutual electric resistance is interposed between eachtwo of the supply electrodes A through F. Alternatively, one tester maybe provided to check the resistance between each two of the supplyelectrodes A through F by switching the electrodes.

A voltage is applied between the processing electrode 11 and the supplyelectrodes A through F by a DC low-voltage supply 15, and anelectrolytic solution (a slurry) 17 is supplied onto the upper face ofthe wafer W by a supply nozzle 16. The electrolytic solution 17 maysuitably be phosphoric acid, sodium nitride, ammonium chloride, sulfuricacid, hydrochloric acid, or a mixed solution of them.

The electrode portion is made of carbon or the like. If a hydroplanestate is formed with the water film of the electrolytic solution 17 whenan electrode is brought close to the wafer W, the interelectrode spacecan be made very small, and the convex portion on the wafer W iselectrolytically concentrated. Thus, only the convex portion can beselectively processed and removed.

The electrode portion should desirably have a flat shape with respect tothe surface of the wafer W facing the electrode. If the electrodebecomes large in size, however, the relationship between the electrodeand the surface of the wafer W becomes equal to a relationship betweenflat faces, and the electrode might be partially brought into contactwith the surface of the wafer W. If there is a contact, short-circuitingmight be caused, and the wafer W is damaged by the hard carbon.Therefore, it is preferable that the electrode area is made so smallthat there is not a contact portion in the plane, while the very smallspace is maintained. The desirably effective electrode area isapproximately +20 mm.

In a case where only the electrolytic dissolution processing isperformed, a nonconductive film might be formed on the surface,particularly with Cu, Ta, or the like. In such a case, the current mightrapidly decrease, and the processing might not proceed at a certainspot. In this case, an electrode in the form of a carbon brush issuitable as the electrode. With a brush-like shape, the top end of theelectrode is in contact with the surface of the wafer W. However, whenan electrolytic solution is supplied while the wafer W is rotated, thetop end is not completely in contact with the surface of the wafer W,and a very small space is maintained between the electrode and thesurface of the wafer W.

For example, if a carbon brush is formed with brushes each having alarge number of thin bristles of approximately 0.15 mm tied together,constant pressure is applied onto the surface of the wafer W from thetop end of one brush, though the pressure is very small as each brushbends. With this pressure, an even smaller space is formed between thewafer W and the carbon brush electrode. Due to the space, electrolyticprocessing can be selectively performed on the convex portion of thewafer W.

At the time of electrolytic processing, while the electrolytic solution17 is being supplied between the rotating wafer W and the processingelectrode 11, electrolytic polishing is performed by applying a voltage,so that the conductive film on the upper face of the wafer W can beevenly removed. In this case, the processing electrode 11 is graduallyscan-moved from the center of the wafer W toward the outer peripheralportion.

The processing is completed at the center of the wafer W, and theprocessed region is widened toward the outer peripheral portion. In thismanner, uniform processing can be performed on the entire surface of thewafer W. When scanning is performed with the movable member (arm) 12having the processing electrode 11, the scan speed should be changed inaccordance with the processed state of the wafer W.

The processed state of the surface of the wafer W can be monitored by asensor attached to the scan arm for the electrolytic processing. Thesensor can sense changes in the color of the surface of the wafer W. Ina case where the wafer W is made of Cu, a clear change in the film colorcan be observed when the type of film is switched from a Cu film to a Tafilm.

As the sensor that can sense changes in the color of the surface, aspectrometer or the like may be used. With a spectrometer, light isdispersed by a prism or grating, and the intensity distribution of thedispersed light at each wavelength is measured with the use of a LinearImage Sensor S3901/S3904 series (manufactured by Hamamatsu Photonics K.K.). In this manner, changes in the film color can be detected with highprecision.

After the electrolytic processing, a rinsing procedure is carried out toremove the electrolytic solution 17 from the surface of the wafer W. Inthe rinsing procedure, the surface of the wafer W is rinsed, and purewater is sprayed to the wafer chucks 21 through 26 and the inside of theprocess washing cup provided below them, so as to rinse off the waferchucks 21 through 26 and the inside of the process washing cup.

In the washer 3, the wafer W after the electrolytic processing is washedwith a pen brush. The pen brush is suitably a sponge made of polyvinylalcohol (PVA). First, the wafer W is rotated, and a washing chemicalsolution or water is supplied to the portion surrounding the center ofthe surface of the wafer W. The wafer W is then scanned with the penbrush, so that the surface of the wafer W can be cleaned (the primarywashing).

There might be particles remaining on the surface of the wafer W evenafter the washing. In such a case, the surface of the wafer W should berinsed with pure water. Particularly, when the wafer W is washed withultrasonic waves, the particles remaining on the surface of the wafer Wcan be completely removed (the secondary washing).

The pen brush and the ultrasonic generator are attached to the top end20 of a washing movable arm 19 that is horizontally rotatable about avertical axis 18. The washing movable arm 19 is provided in the vicinityof the other side of the wafer holding table 8. Accordingly, the penbrush and the ultrasonic generator provided at the top end 20 of themovable arm 19 moves in the radial direction of the wafer W, as thewashing movable arm 19 is horizontally rotated.

Also, there are cases where the remnant cannot be removed by physicalwashing with the pen brush, depending on the material. To counter such asituation, a chemical nozzle (not shown) is provided and is directedtoward the wafer W. Particularly, the additive component and thedissolved metal component of the electrolytic solution might become acontaminating component and adversely affect the wafer W.

To eliminate such a contaminating component of the wafer W, an acidicchemical solution such as hydrofluoric acid or hydrochloric acid may beused, or an alkaline chemical solution such as ammonia may be used. Thecontamination is removed with such a chemical solution and the penbrush, and at the same time, the particles remaining on the surface ofthe wafer W may be removed.

The used chemical solution is also drained off, coming into contact withthe cup surrounding the wafer W. Also, the scattered chemical solutionis constantly rinsed off with a pure water shower within the cup.Accordingly, when electrolytic processing is performed again, thechemical solution used for the washing does not have adverse influence.

In the procedure for rinsing off the used chemical solution, pure waterwashing may be performed with ultrasonic waves. With ultrasonic waves,the chemical solution remaining on the surface of the wafer W can bemore effectively rinsed off, and the chemical solution remaining insidethe cup can be completely washed away.

In the drying procedure to be carried out at last, the surface of thewafer W is rinsed with pure water. Immediately after that, spin dryingcan be performed. The wafer chucks 21 through 26 can revolve, with themaximum number of revolutions being 2000 rpm.

A polishing head and a polishing platen that are normally used inelectrolytic polishing are very large and heavy, and as a result,produce a vibration in the entire device when revolving at a high speed.However, with the light-weight wafer chucks 21 through 26 in accordancewith the present invention, washing can be performed after electrolyticprocessing, and drying is then performed by spinning the wafer chucks 21through 26 at a high speed, with the maximum number of revolutions being2000 rpm.

In a process using a low-k material, the surface of the wafer W haswater repellency, and therefore, a watermark sometimes appears. In sucha case, normal spin drying is not suitable. One of the reasons for theappearance of a watermark is that water is not removed as a whole but isdivided into droplets of water due to the water repellency of thesurface of the wafer W. It is believed that those droplets absorboxygen, and the water containing oxygen reacts with the low-k materialto form a silicon oxide with a different composition.

To counter this problem, the entire module for electrolytic processingand washing and drying is formed in a sealed container housing that iscompact in size. The housing is designed to serve as a pressurecontainer that can withstand up to 10 Pa. Particularly, in the lastdrying procedure, spin drying should be performed with a pressureincreased to approximately 8 Pa in a nitrogen atmosphere.

In a nitrogen atmosphere, a silicon oxide that forms unnecessarywatermarks due to the oxygen contained in pure water is not formed onthe surface of the low-k material. Also, with the increased pressure,the contact angle of the water is increased, and an environment that isnot water repellent in appearance can be formed. With such anenvironment, formation of watermarks can be prevented even when spindrying is performed.

By another method for preventing formation of watermarks due to spindrying, alcohol such as IPA may be incorporated into the pure water tobe supplied in the rinsing procedure prior to the spin drying. The watercontaining IPA increases the wetness of the surface of the wafer W, anddramatically increases the contact angle. As a result, even after normalspin drying is performed, watermarks are not formed on the surface ofthe wafer W, and a dry surface can be maintained.

In the wafer drier 4, the washed wafer W is subjected to spin drying. Inthis case, the wafer chucks 21 through 26 attached during theelectrolytic processing may be detached or may not be detached from thewafer W. After that, the wafer W is spun around, so that theelectrolytic solution and water remaining on the surface of the wafer Wcan be thrown off and eliminated.

Instead of pure water, an aqueous solution containing alcohol may beused. With such an aqueous solution, the surface tension can be reduced,and the spin drying becomes easier. Particularly, for a low-k materialhaving a water-repellent surface, such a process is suitable.

Referring now to FIG. 4, an example of the operation of processing thewafer W in accordance with this embodiment is described. First, thewafer W is transported to the processing chamber 5 by the robot 6, andis placed on the wafer holding table. The wafer W is then fixed to thewafer holding table by the wafer chucks 21 through 26. This fixing isperformed to bring the power supply unit into contact with the surfaceof the wafer W at the same time as the fixing. Also, the fixing isperformed to secure the wafer W at the center of the wafer holdingtable. The vacuum chuck of the wafer holding table forms a vacuum forthe secured wafer W, so as to firmly attach the wafer W onto the waferholding table 8.

While an electrolytic solution is being applied onto the surface of thewafer W, the processing electrode 11 attached to the top end of the scanarm is caused to act on the surface of the wafer W, so that electrolyticprocessing is performed. In the electrolytic processor 2, the conductivefilm (a Cu film or a Ta film) on the surface of the wafer W is removedby electrolytic polishing. More specifically, a voltage is appliedbetween the rotating wafer W and the processing electrode 11 while theelectrolytic solution 17 is being supplied, and the processing electrode11 is caused to scan the wafer W from the center toward the outerperiphery of the wafer W. In this manner, the conductive film on thesurface of the wafer W is gradually and evenly removed from the centertoward the outer periphery of the wafer W (step S1).

After the conductive film is evenly removed from the center to the outerperiphery of the wafer W, an anticorrosion solution is applied from thecenter to the outer periphery of the wafer W. The ring-like Cu filmremaining at the outer periphery of the wafer W at the end of theelectrolytic processing is removed by etching or mechanical processingin the beveling unit 7 (step S2).

The wafer W subjected to the electrolytic processing is not moved andremains in the same position. The wafer W is then washed by the washer 3as a different arm from the scan arm for the electrolytic processing.More specifically, the pen brush is brought into contact with thesurface of the wafer W, and the surface of the wafer W is washed byjetting a washing solution or pure water. After that, the surface of thewafer W is rinsed with pure water having ultrasonic waves appliedthereto (steps S3 and S4).

The washed wafer W is then subjected to spin drying in the drier 4. Morespecifically, the wafer W is spun around on the wafer holding table 8,so that the electrolytic solution 17 and water remaining on the surfaceof the wafer W are thrown off due to the centrifugal force (step S5).

As described above, in this embodiment, the electrolytic processor 2,the washer 3, and the drier 4 are placed in the processing chamber 5, soas to form one module. Accordingly, not only the entire device and thespace for the device can be made smaller, but also the electrolyticprocessing, the washing, and the drying of the wafer W can besequentially performed in one place in a continuous manner.

To maintain cleanness, a downward air current is supplied to the modulethat performs the electrolytic processing, the washing, and the dryingof the wafer W, from the above via a hepafilter. Accordingly, the waferW and its surrounding area are constantly in a clean air current. Thus,after the drying of the wafer W at last, the wafer W having a cleansurface without remnant particles can be transferred to thetransportation robot.

To counter the problem of watermarks at the time of electrolyticprocessing or washing and drying, N₂ blowing may be performed on thewafer W and its surrounding area in the module. A N₂ nozzle to introduceliquid nitrogen is placed on the wafer W, and cooled N₂ is supplied tothe wafer W and its surrounding area. In this manner, the wafer W andits surrounding area can be separated and isolated from the atmospherecontaining oxygen.

Since there is no oxygen in the atmosphere, oxidation of the Cu surfacecan be prevented during the electrolytic processing, and formation ofwatermarks formed by the oxygen that is contained in the pure water andreacts with the surface of the low-k material can be prevented duringthe wafer drying procedure.

Accordingly, even if some trouble is caused in one of the electrolyticprocessor 2, the washer 3, and the drier 4 of the module, the troubledoes not adversely affect the processing procedures in other modules.Therefore, it is not necessary to interrupt the processing procedures inother modules, and oxidation degradation and corrosion due to theinterruption are not caused. Furthermore, it is not necessary to preparea complicated program.

FIGS. 5 and 6 show other examples of the electrolytic processing unitdevice 1 in accordance with the present invention. In these examples,the electrolytic processor 2, the washer 3, and the drier 4 are arrangedin a circular arc or in a straight line in the processing chamber 5. Thewafer W is transported to the electrolytic processor 2, the washer 3,and the drier 4 by a double-arm robot 27 that can move in a desireddirection (can move straight and spin around). It is also possible toprovide two robots 27 that are interposed between electrolyticprocessors 2, washers 3, and driers 4, as shown in FIG. 7. The tworobots 27 are designed to move independently of each other.

In any of these structures, electrolytic processing, washing, and dryingof the wafer W can be performed with one module. Accordingly, even ifsome trouble is caused in the module, the processing of other wafers Win other modules is not interrupted. Furthermore, the mechanism ofrotating a polishing pad that is necessary in a conventional CMP devicecan be omitted, and the amount of mechanical processing can be reduced.Thus, the device mechanism can be simplified and made more lightweight.

Unlike a conventional structure having more than one module for each ofthe procedures of electrolytic processing, washing, and drying, thedevice in accordance with the present invention does not require amechanism for transporting each wafer W between the modules. Thus, themechanism and the processing program can be further simplified.

In the above described embodiment, the number of electrolyticprocessors, the number of washers, and the number of driers in oneelectrolytic processing unit device are one. However, it is possible toemploy two or more electrolytic processors, two or more washers, and twoor more driers, if necessary.

As described above, in the present invention, the electrolyticprocessor, the washer, and the drier that form one module are connectedby one transportation system. Accordingly, only one device fortransporting the wafer W to the electrolytic processor, the washer, andthe drier is required. With the one device for transportation, the waferW can be continuously transported to the electrolytic processor, thewasher, and the drier. Thus, the costs for the wafer transportationsystem can be reduced, and the operation rate of the wafer transportingdevice can be made higher.

Furthermore, the electrolytic processor, the washer, and the drier canbe operated, controlled, and subjected to maintenance independently ofone another. Accordingly, when one of the electrolytic processor, thewasher, and the drier is operated, controlled, or subjected tomaintenance, the operations at the other components do not need to bestopped. Thus, the operating rates of the electrolytic processor, thewasher, and the drier can be made higher.

Further, the washing arm supporting the wafer washing unit is providedto face the arm that holds the electrolytic processing head, so that thewafer W is washed at a spot separated from the spot for the electrolyticprocessing. Thus, the electrolytic solution used for the electrolyticprocessing cannot be brought into the washer.

Since the wafer washing unit includes a washing brush, a ultrasonicwater supplier, and a nitrogen blower, the electrolytic solutionremaining on the surface of the wafer W can be removed by brush washingand ultrasonic washing, and the space surrounding the wafer W cannotbecome an oxygen atmosphere during the washing. Thus, the effectivenessof washing the wafer W is increased, and the wafer W is not adverselyaffected by an oxygen atmosphere.

Since the electrode portion is made of an inorganic material, the oldelectrolytic solution used for electrode processing cannot remain at theelectrode portion. Accordingly, when electrolytic processing isperformed with a new electrolytic solution, a reaction between the newelectrolytic solution and the old electrolytic solution can beprevented.

Furthermore, the series of procedures of electrolytic processing, edgeprocessing, washing, and drying for the wafer W are carried out in thesame position. Accordingly, the wafer W does not need to be moved foreach procedure, and the series of procedures can be carried out in acontinuous manner.

In this embodiment, the surface of the wafer W and the electrode portionare rinsed with pure water after electrolytic processing and washing.Through the rinsing, the electrolytic solution and chemical solutionremaining on the surface of the wafer W at the time of electrolyticprocessing and washing can be thoroughly removed. In this manner,degradation of the processing quality of the wafer W due to theelectrolytic solution and chemical solution can be effectivelyprevented.

It should be understood that various changes and modifications may bemade to the above embodiments, without departing from the scope of theinvention, and the present invention is applicable to the changes andmodifications.

1. An electrolytic processing unit device comprising: an electrolyticprocessor that performs electrolytic processing on a wafer; a washerthat washes the processed wafer; and a drier that dries the processed orwashed wafer, the electrolytic processor, the washer, and the drierbeing placed in a processing chamber to form one module that performsthe electrolytic processing, washing, and drying for the wafer.
 2. Theelectrolytic processing unit device according to claim 1, wherein theelectrolytic processor, the washer, and the drier are aligned on acircular arc or a straight line.
 3. The electrolytic processing unitdevice according to claim 1 or 2, wherein the electrolytic processor,the washer, and the drier form one module, and are connected to eachother by one transportation system.
 4. The electrolytic processing unitdevice according to any of claims 1 through 3, wherein the electrolyticprocessor, the washer, and the drier that carry out the above series ofprocedures are controlled, operated, and subjected to maintenanceindependently of one another.
 5. The electrolytic processing unit deviceaccording to claim 1 or 2, wherein a beveling unit for beveling an outerperipheral portion of the wafer after the electrolytic processing isprovided in the vicinity of the electrolytic processor.
 6. Theelectrolytic processing unit device according to any of claims 1, 3, and4, wherein the module includes: an access area through which wafers arebrought in and out; an electrolytic processing head for electrolyticprocessing that is provided in a different area from the access area,and a holding arm that holds the electrolytic processing head; and awashing arm that supports a wafer washing unit is provided in theopposite position from the holding arm.
 7. The electrolytic processingunit device according to claim 6, wherein the wafer washing unit in themodule includes a washing brush, a ultrasonic water supplier, and anitrogen blower.
 8. An electrolytic processing unit device comprising:an electrolytic processor that performs electrolytic processing on awafer; a washer that washes the processed wafer; and a drier that driesthe processed or washed wafer, the electrolytic processor, the washer,and the drier being placed in a processing chamber to form one modulethat performs the electrolytic processing, washing, and drying for thewafer, an electrode portion for the electrolytic processing being madeof an inorganic material.
 9. A method for electrolytic processing,washing, and drying in a structure having a wafer chuck mechanism,comprising the steps of: performing electrolytic processing by applyinga voltage between an electrode having edges clamped around a wafer andan electrolytic processing head that scans the surface of the wafer,after securing the wafer; polishing a conductive film at an edge portionin the same position, if necessary, while a bottom face of the wafer isbeing sucked and fixed after an edge clamp is removed; scanning thesurface of the wafer with a washing arm in the same position, a washingunit being attached to the washing arm; washing the processed wafer; anddrying the processed or washed wafer in the same position.
 10. Themethod according to claim 9, wherein the surface of the wafer and anelectrode portion are rinsed with pure water, after the electrolyticprocessing procedure and the washing procedure.